Dept. of Analytical Chemistry, University of Granada, Av. Fuente Nueva s/n, 18071, Spain; Department of Chemistry, Semnan University, Semnan, 2333383-193, Iran.
Dept. of Analytical Chemistry, University of Granada, Av. Fuente Nueva s/n, 18071, Spain.
J Chromatogr A. 2019 Dec 20;1608:460409. doi: 10.1016/j.chroma.2019.460409. Epub 2019 Jul 29.
In this study two different analytical approaches have been developed to determine the presence of several cyanotoxins in saline water samples from a continental salt marsh. A salting-out assisted liquid-liquid extraction (SALLE) has been used in combination with ultra-high performance liquid chromatography-tandem mass spectrometry and UV-diode array detection (UHPLC-MS/MS and UHPLC-DAD). The target analytes are eight microcystins named MC-RR, MC-YR, MC-LR, MC-WR, MC-LA, MC-LY, MC-LW, MC-LF and nodularin (NOD), covering a wide range of polarities. The separation was achieved using a Zorbax Eclipse Plus RRHD C18 column (50 × 2.1 mm, 1.8 μm) in less than 7.5 and 5.5 min for UV and MS/MS detection, respectively. The mobile phase used consisted of water (solvent A) and acetonitrile (MeCN) (solvent B), both containing 0.01% of formic acid for DAD and 0.4% of formic acid for MS/MS detection, at a flow rate of 0.4 mL min. The temperature of the column was set at 25 °C and 20 μL of sample were injected. The main parameters affecting the SALLE procedure were studied and the following optimum values were obtained: neutral pH, 2 mL of acetonitrile as extraction solvent and 1.2 g of ammonium sulfate as salting-out agent for 4 mL of water sample. The validation protocols for both methods were accomplished with real water samples obtaining LODs ranging from 1.0 to 3.4 μg L and 0.02 to 0.11 μg L for DAD and MS/MS respectively. Although the SALLE-UHPLC-DAD methodology is easier and cheaper than UHPLC-MS/MS significantly better detection limits were achieved with tandem mass spectrometry as well as allowing for unambiguous identification. Extraction recoveries were higher than 77.0% (except for MC-RR and NOD which were 53.2% and 54.3, respectively) with satisfactory inter-day and intra-day precisions (RSD below 13.3%).
在这项研究中，开发了两种不同的分析方法来检测来自大陆盐沼的盐水样本中几种蓝藻毒素的存在。盐析辅助液液萃取（SALLE）与超高效液相色谱-串联质谱和紫外二极管阵列检测（UHPLC-MS/MS 和 UHPLC-DAD）相结合使用。目标分析物是八种微囊藻毒素，分别命名为 MC-RR、MC-YR、MC-LR、MC-WR、MC-LA、MC-LY、MC-LW、MC-LF 和节球藻毒素（NOD），涵盖了广泛的极性范围。使用 Zorbax Eclipse Plus RRHD C18 柱（50×2.1mm，1.8μm）在不到 7.5 和 5.5min 内分别用于 UV 和 MS/MS 检测来实现分离。用于检测的流动相由水（溶剂 A）和乙腈（MeCN）（溶剂 B）组成，两者均含有 0.01%的甲酸用于 DAD 检测和 0.4%的甲酸用于 MS/MS 检测，流速为 0.4mL min。柱温设定为 25°C，进样量为 20μL。研究了影响 SALLE 过程的主要参数，并获得了以下最佳值：中性 pH 值、2mL 乙腈作为萃取溶剂和 1.2g 硫酸铵作为 4mL 水样的盐析剂。两种方法的验证方案均使用实际水样完成，得到的 LOD 范围分别为 1.0 至 3.4μg/L 和 0.02 至 0.11μg/L，用于 DAD 和 MS/MS 检测。尽管 SALLE-UHPLC-DAD 方法比 UHPLC-MS/MS 更简单、更便宜，但串联质谱法可获得更好的检测限，同时也可实现明确的鉴定。萃取回收率均高于 77.0%（除 MC-RR 和 NOD 外，回收率分别为 53.2%和 54.3%），日内和日间精密度良好（RSD 低于 13.3%）。
